High-Accuracy Frequency Standard Comparison Technology Combining Adaptive Frequency and Lissajous Figure

To meet the requirements of high-precision measurement of time-frequency multiparameters, a high-accuracy frequency standard comparison technology combining adaptive frequency and Lissajous figure is proposed. This technology uses only one reference frequency source to realize the frequency standard comparison and frequency measurement between any frequency signals without frequency normalization. First, a new frequency standard comparison signal is obtained by using an adaptive frequency standard generation module to roughly measure the measured frequency. Second, the turning period is measured by observing the Lissajous figure. Third, via the turning period and the function relation of frequency deviation, the relative frequency difference between the measured and frequency standard signals can be obtained. Finally, the phase relation between the measured and frequency standard signals is determined by oscilloscope, and then the high-accuracy measurement of the measured frequency can be realized. The testing results indicate that the accuracy of the frequency measurement in the radiofrequency range can achieve the $10^{-12}$ order of magnitude. Compared with the traditional frequency standard comparison technology, this technology has many characteristics, such as simple operation, low cost, low noise, and high measurement accuracy.